buzzing noise from exhaust - turbo?

[jt15833]

After I got my car dyno'd, my car was making a strange "buzzing" noise that from inside the car sounded very much like it was coming from the rear exhaust / muffler area. I thought it was definitely turbo related, my guess was the impeller blades were contacting the housings, mainly the turbine blade/housing.

Well I replaced the turbo, with an SR T25 that to me felt like it had slim-none shaft play and I couldn't see these blades contacting the housings. However when I got my CA T25 off it wasn't in that bad of shape either...Long story short, I replaced the turbo last night and today it feels like it is making about the same noise. A distinct buzzing that to the best of my knowledge sounds like its coming from the muffler area. I had the car jacked up on one side and idling and I could hear it from underneath, but was unable to pin point it. I tried sticking a screwdriver to the exhaust, turbo, manifold etc and listening closer but no luck.

These are the conditions it makes the noise-Slight engine braking-Slight acceleration (around 0 pressure)-Constant throttle acceleration

I'm starting to think that it's not turbo related. What are the chances that both T25's I've had on there make almsot the exact same noise? Maybe I shot something into the muffler? My next step is to remove the cat or downpipe and see how the sound is effected.

Any input appreciated.

[Two-Fortee]

unbolt your down pipe from your o2 housing and see how it sounds. It could just be your muffler or exhaust vibrating. Best of luck with it.

[ca18detgabby]

sounds like a leak in the exhaust. maybe one of the gaskets is allowing a small amount out and causing that noise.